1. Field of the Invention
This invention describes acid stable surfactant materials.
2. Description of the Art
Ordinarily surfactant compositions are formulated at an alkaline pH. Thus most laundry products or bottle cleaning formulations have an in-use pH of from about 8 to about 12. It is however, desirable when formulating certain hard surface cleaning compositions to utilize a high acid content such as a pH of 2 or less.
The highly acid cleaning compositions are often used where there are salt deposits such as from milk acids (milkstone), or calcium or magnesium carbonate deposites such as in toilets or in equipment in which relatively hard wataer is utilized. Iron salts are also ordinarily removed with acid cleaning compositions.
Conventional surfactants for cleaning hard surfaces are described in U.S. Pat. No. 3,591,510 to Zenk issued July 6, 1971. An article entitled A Greasy Soiled Hard Surface Cleaning Test by Morris A. Johnson, JAOCS, Volume 61, No. 4, pages 810-813 (April 1984), describes a series of commercially available solvent-based and water-based cleaners useful for removing greasy soil. Further disclosures of hard surface cleaning formulations are also discussed in Formulation of Hard Surface Spray Cleaners by Johnson et al as reported in detergents and specialties, June 1969, pages 28-32 and 56.
Uses and combinations of glycosides are disclosed in Rohm and Haas publications CS-400 and CS-449 dated January 1978 and November 1979 respectively.
It is also known that oil wells are advantageously acidized to open the rock formations to allow free drainage of oil into a sump from which it is more easily pumped. In such formulations, it is desirable that a surfactant be included to assist in carrying the dissolved rock. This may be accomplished through a surfactants' foam forming ability. It is also desirable in the acid treatment of oil bearing strata to have the surfactant foam sufficiently to fracture the rock. The surfactant desirably loses its foaming capacity following acidization or fractionation in that the foam would inhibit the flow of the oil through the formation which is contrary to the stated purpose of providing free flow of the oil.
It is known from Arnaudis in European Published Application No. 0077167 dated Apr. 20, 1983 that strong acids in combination with reducing acids may be used to prepare glycosides. Urfer, in U.S. patent application Ser. No. 06/668,762 filed Nov. 6, 1984 discloses weak buffering acids in combination with glycosides.
It has now been found that glycoside surfactants of the type described herein have excellent stability under highly acid conditions. The glycosides which are excellent surfactant materials provide sufficient foaming in hard surface cleaners so that the remainder of the composition e.g., acid, does not merely run off of the surface being cleaned. It is also observed that the glycoside surfactant is one which is stable but which eventually will cease foaming, therefore making it an excellent acidizing or fracturing surfactant.
Throughout the specification and claims, percentages and ratios are by weight, temperatures are in degrees of Celsius and pressures are in KPascals over-ambient unless otherwise indicated. To the extent that the references cited herein are applicable to the present invention, they are incorporated herein by reference.